Diamines containing pendent phenylethynyl groups

ABSTRACT

Controlled molecular weight imide oligomers and co-oligomers containing pendent phenylethynyl groups (PEPIs) and endcapped with nonreactive or phenylethynyl groups have been prepared by the cyclodehydration of the precursor amide acid oligomers or co-oligomers containing pendent phenylethynyl groups and endcapped with nonreactive or phenylethynyl groups. The amine terminated amide acid oligomers or co-oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and diamine containing pendent phenylethynyl groups and subsequently endcapped with a phenylethynyl phthalic anhydride or monofunctional anhydride. The anhydride terminated amide acid oligomers and co-oligomers are prepared from the reaction of diamine(s) and diamine containing pendent phenylethynyl group(s) with an excess of dianhydride(s) and subsequently endcapped with a phenylethynyl amine or monofunctional amine. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone and N,N-dimethylacetamide under nitrogen at room temperature. The amide acid oligomers or co-oligomers are subsequently cyclodehydrated either thermally or chemically to the corresponding imide oligomers. The polymers and copolymers prepared from these materials exhibit a unique and unexpected combination of properties that includes higher glass transition temperatures after curing and higher retention of neat resin, adhesive and carbon fiber reinforced mechanical properties at temperatures up to 204° C. under wet conditions without sacrificing melt flow behavior and processability as compared to similar materials. These materials are useful as adhesives, coatings, films, moldings and composite matrices.

ORIGIN OF THE INVENTION

This invention described herein was made by employees of the UnitedStates Government and may be manufactured and used by or for theGovernment or government purposes without payment of any royaltiestherein or thereof.

This is a divisional of application Ser. No. 08/511,422 filed on Aug. 4,1995, now U.S. Pat. No. 5,606,014.

BACKGROUND OF THE INVENTION

Polyimides (PI) are heterocyclic polymers commonly prepared by thecondensation reaction of an aromatic diamine with an aromaticdianhydride or derivative thereof and having a repeat unit of thegeneral structure ##STR1## where Ar is a tetravalent aromatic radicalsuch as 1,2,4,5-tetrasubstituted benzene. Ar may also be abis(o-diphenylene) having the general structure ##STR2## where Y=nil, O,S, SO₂, CO, C(CH₃)₂, or any other appropriate divalent radical. Ar' is adivalent aromatic radical which may be 1,3-phenylene, 1,4-phenylene,4,4'-biphenylene, 4,4'-oxydiphenylene, 4,4'-sulfonyldiphenylene, or anyother appropriate divalent radical.

The synthesis and characterization of PI has been extensively studiedand documented. Reviews on PI are available. J. W. Verbicky, Jr.,"Polyimides" in Encyclopedia of Polymer Science and Engineering, 2^(nd)Ed., John Wiley and Sons, New York, Vol. 12, 364 (1988); C. E. Sroog,Prog. Polym. Sci., 16, 591 (1991)!.

A variety of monomers, oligomers and polymers containing ethynyl(acetylenic) and substituted ethynyl (i.e. phenylethynyl) groups havebeen reported. The ethynyl groups in the polymer is either pendent tothe chain, in the chain, or at the chain ends. Many of these materialshave been used to prepare coatings, moldings, adhesives and compositesP. M. Hergenrother, "Acetylene Terminated Prepolymers" in Encyclopediaof Polymer Science and Engineering, John Wiley and Sons, New York, Vol.1, 61 (1985)!. Good processability by either solution casting and/orcompression molding have been observed for the ethynyl and substitutedethynyl containing materials. In general, thermally cured ethynyl andsubstituted ethynyl containing materials exhibit a favorable combinationof physical and mechanical properties. Some ethynyl endcapped materialssuch as the Thermid® resins are commercially available (National Starchand Chemical Co., Bridgewater, N.J. 08807). Phenylethynyl containingamines have been used to terminate imide oligomers F. W. Harris, A.Pamidimuhkala, R. Gupta, S. Das, T. Wu, and G. Mock, Poly. Prep., 24 (2)325, 1983; F. W. Harris, A. Pamidimuhkala, R. Gupta, S. Das, T. Wu, andG. Mock, J. Macromol. Sci.-Chem., A21 (8 & 9), 1117 (1984); C. W. Paul,R. A. Schultz, and S. P. Fenelli, "High-Temperature Curing Endcaps ForPolyimide Oligomers" in Advances in Polyimide Science and Technology,(Ed. C. Feger, M. M. Khoyasteh, and M. S. Htoo), Technomic PublishingCo., Inc., Lancaster, Pa., 1993, p. 220; R. G. Byrant, B. J. Jensen, andP. M. Hergenrother, Poly. Prepr., 34 (1), 566, 1993!. Imide oligomersterminated with ethynyl phthalic anhydride P. M. Hergenrother, Poly.Prep., 21 (1), 81, 1980!, substituted ethynyl phthalic acid derivativesS. Hino, S. Sato, K. Kora, and O. Suzuki, Jpn. Kokai Tokkyo Koho JP 63,196, 564. Aug 15, 1988; Chem. Abstr., 115573w, 110, (1989)! andphenylethynyl containing phthalic anhydrides have been reported. Imideoligomers containing pendent substituted ethynyl groups F. W. Harris, S.M. Padaki, and S. Varaprath, Poly, Prepr., 21 (1), 3, 1980 (abstractonly), B. J. Jensen, P. M. Hergenrother, and G. Nwokogu, Polymer, 34(3), 630, 1993; B. J. Jensen and P. M. Hergenrother, U.S. Pat. No.5,344,982 (Sep. 6, 1994)! have been reported.

This present invention constitutes new composition of matter. Itconcerns novel diamines containing phenylethynyl groups and new imideoligomers and co-oligomers containing pendent phenylethynyl groups. Thepolymers and copolymers prepared from these materials exhibit a uniqueand unexpected combination of properties that includes higher glasstransition temperatures after curing and higher retention of neat resin,adhesive and carbon fiber reinforced mechanical properties attemperatures up to 204° C. under wet conditions without sacrificing meltflow behavior and processability as compared to similar materials.

Another object of the present invention is to provide materials that areuseful as adhesives, coatings, films, moldings and composite matrices.

Another object of the present invention is the composition of severalnew diamines containing pendent phenylethynyl groups.

SUMMARY OF THE INVENTION

According to the present invention the foregoing and additional objectswere obtained by synthesizing controlled molecular weight imideoligomers and co-oligomers containing pendent phenylethynyl groups andendcapped with phenylethynyl groups or nonreactive groups by differentmethods. Amide acid oligomers and co-oligomers containing pendentphenylethynyl groups (PEPAAs) were prepared by the reaction ofdianhydride(s) with an excess of diamine(s) and diamine containingpendent phenylethynyl group(s) and endcapped with4-phenylethynylphthalic anhydride or phthalic anhydride under a nitrogenatmosphere at room temperature in N-methyl-2-pyrrolidinone (NMP).Additionally, PEPAAs were prepared by the reaction of diamine(s) anddiamine containing pendent phenylethynyl group(s) with an excess ofdianhydride(s) and endcapped with a3-aminophenoxy-4'phenylethynylbenzophenone under a nitrogen atmosphereat room temperature in NMP. The imide oligomers and co-oligomerscontaining pendent phenylethynyl groups (PEPI) were prepared bycyclodehydration of the precursor PEPAA oligomers in NMP by azeotropicdistillation with toluene. The direct preparation of PEPIs has beenperformed in m-cresol containing isoquinoline at elevated temperature.Amide acid oligomers and co-oligomers containing pendent phenylethynylgroups can be prepared by the reaction of diamine(s) and diaminecontaining pendent phenylethynyl group(s) with an excess ofdianhydride(s) and endcapped with a monofunctional amine under anitrogen atmosphere at room temperature in NMP. Imide oligomers andco-oligomers containing pendent phenylethynyl groups can be prepared bythe reaction of the half alkyl ester of aromatic tetracarboxylic acidswith aromatic diamines and diamine containing pendent phenylethynylgroup(s) and endcapped with the half alkyl ester of phenylethynylsubstituted phthalic acid, the half alkyl ester of phthalic acid,phenylethynyl amine, or monofunctional amine by heating in NMP. PEPIsprepared by the alkyl ester route can also be prepared by heating neator in solvents such as m-cresol. Imide oligomers and co-oligomerscontaining pendent phenylethynyl groups can be prepared by thepolymerization of monomeric reactants (PMR) approach by heating amixture of a diamine and diamine containing pendent phenylethynylgroup(s) and the ethyl ester derivatives of dianhydride(s) and endcappedwith phenylethynylphthalic anhydride, monofunctional anhydride,phenylethynyl amine, or monofunctional amine.

In addition, the amine terminated PEPAA oligomer or co-oligomer or theanhydride terminated PEPAA oligomer or co-oligomer can becyclodehydrated to the corresponding amine terminated PEPI or theanhydride terminated PEPI oligomer or co-oligomer, respectively, and theappropriate endcapper subsequently reacted with the soluble amineterminated PEPI oligomer or co-oligomer or the soluble anhydrideterminated PEPI oligomer or co-oligomer, respectively. The PEPI oligomeror co-oligomer must be soluble in order to perform this endcappingreaction. Upon reaction of the amine terminated PEPI oligomer orco-oligomer or the anhydride terminated PEPI oligomer or co-oligomerwith the endcapper, the temperature is increased to effectcyclodehydration to complete imidization.

The inherent viscosities (η_(inh)) of the PEPAA oligomers andco-oligomers ranged from 0.21 to 0.65 dL/g and the η_(inh) of highmolecular weight unendcapped PEPAA was 0.85 dL/g. The glass transitiontemperatures (T_(g)) of the uncured as-isolated PEPIs ranged from209°-269° C. In some cases, a crystalline melt temperature was observedfor the uncured PEPIs. The temperature of onset and peak exotherm due toreaction of the phenylethynyl group was ˜350° C. and ˜411° C.,respectively. After curing at 350° C. for 1 h in a sealed DSC pan theT_(g) of the cured polymers ranged from 255°-313° C. Thermogravimetricanalysis (TGA) at a heating rate of 2.5° C./min of the uncuredas-isolated PEPI powders showed no weight loss occurring below 300° C.in air or nitrogen with a 5% weight loss occurring ˜475° C. in air and˜517° C. in nitrogen. After a thermal cure (350° C./mold/1 h), TGA at aheating rate of 2.5° C./min of the cured polymers showed no weight lossoccurring below 300° C. in air or nitrogen with a 5% weight lossoccurring ˜495° C. in air and ˜510° C. in nitrogen. The tensilestrength, tensile modulus, and break elongation for unoriented thinfilms ranged from 18.9-21.8 ksi, 457-600 ksi, and 4-20% at 23° C.; and10.1-14.0 ksi, 290-411 ksi, and 5-34% at 177° C.; and 9.2-12.2 ksi,267-372 ksi, and 6-30% at 200° C., respectively. The polymers preparedfrom these materials exhibit higher glass transition temperatures withno apparent reduction in melt flow behavior as compared to similarmaterials. The G_(IC) (critical strain energy release rate) ofcompression molded samples of PEPIs ranged from 2.9 in lb/in² to 10.3 inlb/in². The titanium (Ti) to Ti tensile shear properties performed onPASA Jell 107 surface treated adherends were 3900 at 23° C. and 4100 at177° C. The Ti to Ti tensile shear properties performed on chromic acidanodized (5V) surface treated adherends were 4300 at 23° C. and 4100 at177° C. The flexural properties of composite panels with aunidirectional lay-up gave flexural strength and flexural modulus whichranged from 233.5-260.3 ksi and 21.08-21.52 Msi at 23° C. and190.3-219.4 ksi and 18.73-20.58 Msi at 177° C., respectively. Ingeneral, composite specimens exhibited higher mechanical properties whentested at room temperature and better retention of those properties whentested at 177° C. than similar materials.

The diamines containing pendent phenylethynyl group(s) were prepared bythe palladium catalyzed reaction of phenylacetylene with bromosubstituted dinitro compounds and subsequently reduced to thecorresponding diamines containing pendent phenylethynyl group(s) asshown in FIG. 1. The catenation of the phenylethynyl group on the phenylring may be para or meta and multiple phenyl rings may have mixedconnecting positions. In general, this synthethic route to diaminescontaining pendent phenylethynyl groups is more cost effective thanother routes. The general reaction sequence for the synthesis of bothuncontrolled and controlled molecular weight polymers and copolymers isrepresented in FIGS. 2, 3, 4, 5 and 6.

The polymers and copolymers prepared from these materials exhibit aunique and unexpected combination of properties that includes higherglass transition temperatures after curing, higher tensile moduli andhigher retention of neat resin, adhesive and carbon fiber reinforcedmechanical properties at temperatures up to 204° C. when wet withoutsacrificing melt flow behavior and processability as compared to similarmaterials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of the synthesis of diamines containing pendentphenylethynyl groups according to the present invention;

FIG. 2 is a schematic of the synthesis of controlled molecular weightamide acid and imide co-oligomers containing pendent phenylethynylgroups chain terminated with nonreactive or reactive phthalic anhydridebased encapping agents according to the present invention;

FIG. 3 is a schematic of the synthesis of controlled molecular weightamide acid and imide co-oligomers containing pendent phenylethynylgroups chain terminated with nonreactive or reactive aniline basedencapping agents according to the present invention;

FIG. 4 is a schematic of the synthesis of controlled molecular weightamide acid and imide oligomers containing pendent phenylethynyl groupschain terminated with nonreactive or reactive phthalic anhydride basedencapping agents according to the present invention;

FIG. 5 is a schematic of the synthesis controlled molecular weight amideacid and imide oligomers containing pendent phenylethynyl groups chainterminated with nonreactive or reactive aniline based encapping agentsaccording to the present invention; and

FIG. 6 is the reaction sequence for preparation of uncontrolledmolecular weight polyimide containing pendent phenylethynyl groups whereR is a 4-benzoyl group and Ar is 3,3'4,4'-diphenylether.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Novel diamines containing pendent phenylethynyl groups were preparedaccording to FIG. 1 having the following chemical structure: ##STR3##wherein R is a radical selected from the group consisting of: ##STR4##The best results were obtained with3,5-diamino-4'-phenylethynylbenzophenone.

Controlled molecular weight amide acid and imide co-oligomers containingpendent phenylethynyl groups and chain terminated with eithernonreactive or reactive phthalic anhydride based endcapping agents wereprepared according to FIG. 2. The chemical structures of these oligomersare indicated below: ##STR5## wherein Ar is a member selected from thegroup consisting of: ##STR6## wherein Y is a bond or Y is a radicalselected from the group consisting of: O, CO, SO₂, C(CF₃)₂,isophthalpyl, terephthaloyl, 1,3-diphenoxy and 1,4-diphenoxy.

wherein Ar' is a member selected from the group consisting of: ##STR7##wherein the catenation is selected from the group consisting of 2,2';2,3'; 2,4'; 3,3'; 3,4'; and 4,4' and X is a bond or X is a radicalselected from the group consisting of: ##STR8## wherein W is a radicalselected from the group consisting of: H, ##STR9## wherein R is aradical selected from the group consisting of: ##STR10## wherein theamount of diamine containing pendent phenylethynyl groups ranges from1-99 mole %.

Particularly good results were obtained with examples 2, 8 and 13.Polymer characterization is presented in Table 1, thin film mechanicalproperties are presented in Table 2, adhesive properties are presentedin Table 3 and carbon fiber reinforced composite properties arepresented in Table 4.

                  TABLE 1                                                         ______________________________________                                        Imide Oligomers of M .sub.n (calcd) = 5000 g/mol                              containing pendant phenylethynyl groups                                                        ηinh,.sup.3                                                                       Tgi           5% Wt. Loss                            Imide  .sub.ηinh, dL/g.sup.2                                                               dL/g    (Tm),4  Tgc,  in air.sup.5                           Oligomer.sup.1                                                                       (Amide acid)                                                                            (Imide) °C.                                                                            °C.                                                                          initial                                                                            cured                             ______________________________________                                        1      0.85      --      ND.sup.6                                                                              300   --   465                                                                (TMA)                                        2      0.33      --      240     279   446  493                               3      0.65      --      265     297   458  476                               4      0.32      0.28    217 (276)                                                                             255   451  487                                                                (369)                                        5      0.31      0.22    230 (272,                                                                             293   436  451                                                        286)                                                 6      0.26      0.24    209 (278)                                                                             300   478  --                                7      --        0.29    224     283   496  496                               8      0.32      0.28    231 (282)                                                                             313   465  532                               9      0.21      0.41    223 (274)                                                                             310   463  502                               10     0.28      --      269     296   451  487                               11     0.36      --      ND      ND    446  481                               12     0.30      --      ND      260   447  487                               13     0.29      0.32    224 (284)                                                                             289   499  511                               14     0.35      0.26    (243, 262)                                                                            310   499  460                               15     0.33      0.31    231     299   490  464                               16     0.22      --      ND      ND    402  --                                17     0.31      --      ND      ND    413  --                                ______________________________________                                         .sup.1 Number corresponds to Example number                                   .sup.2 Determined on 0.5% (w/v) NMP solutions of the amide acid at            25° C.                                                                 .sup.3 Determined on 0.5% (w/v) mcresol solutions of the imide at             25° C.                                                                 .sup.4 Determined by DSC at 20° C./min. i = asisolated oligomer, c     = cured sealed DSC pan/350° C./1 h                                     .sup.5 Determined by TGA at 2.5° C./min                                .sup.6 ND: not detected                                                  

                  TABLE 2                                                         ______________________________________                                        Unoriented Thin film tensile properties of Imide Oligomers of                 M .sub.n (calcd) = 5000 g/mol containing pendant phenylethynyl groups               T.sub.g,                                                                             Test Temp.,                                                                             Strength,                                                                              Modulus,                                                                             Elongation                             Imide.sup.1                                                                         °C..sup.2                                                                     °C.                                                                              ksi      ksi    at Break, %                            ______________________________________                                        2     --     23        21.8     600    4                                                   177       14.0     411    5                                                   200       12.0     372    6                                      5     289    23        23.5     563    8                                                   177       12.7     370    6                                                   200       12.2     370    9                                      7     290    23        18.9     495    12                                                  177       10.8     301    34                                                  200       9.2      276    25                                     8     --     23        20.2     497    10                                                  177       11.4     322    9                                                   200       9.9      267    17                                     9     306    23        20.5     495    20                                                  177       12.1     296    27                                                  200       10.7     299    30                                     13    301    23        20.4     492    15                                                  177       11.2     307    24                                                  200       9.9      285    28                                     14    294    23        19.8     489    12                                                  177       10.7     290    11                                                  200       10.3     329    11                                     15    296    23        19.5     457    16                                                  177       10.1     291    20                                                  200       9.2      299    12                                     ______________________________________                                         .sup.1 Number corresponds to Example number.                                  .sup.2 Determined by DSC at 20° C./min on film samples cured at        100, 225, 350° C. for 1 h each in flowing air.                    

                  TABLE 3                                                         ______________________________________                                        PRELIMINARY Ti-to-Ti                                                          TENSILE SHEAR PROPERTIES                                                      ______________________________________                                        0.85 3,4'-ODA/0.15 DPEB/BPDP/PA (Example 2)                                   PASA Jell 107 Surface Treatment                                               Test           Strength,                                                                              Cohesive                                              Temp., °C.                                                                            MPa      Failure, %                                            ______________________________________                                         23            3900     60                                                    177            4100     60                                                    ______________________________________                                        0.85 3,4'-ODA/0.15 DPEB/BPDP/PA (Example 2)                                   Chromic Acid Anodized (5V) Surface Treatment                                   23            4300     75                                                    177            4100     75                                                    ______________________________________                                         *Processing conditions: 200 psi/300° C./0.5h, then 200                 psi/350° C./1 h                                                   

    0.70 3,4'-ODA/0.15 APB/0.15 DPEB/BPDA/PEPA (Example 13)                       PASA Jell 107 Surface Treatment                                                               Test        Strength,                                                                              Failure,                                 Processing Conditions                                                                         Temperature, °C.                                                                   psi      %                                        ______________________________________                                        350° C./200 psi/1h                                                                     23          5000     50 C                                     371° C./200 psi/1h                                                                     23          4800     60 C                                     350° C./100 psi/1h                                                                     23          5200     65 C                                     350° C./200 psi/1h                                                                     177         5000     75 C                                     350° C./100 psi/1h                                                                     177         4500     100 C                                    350° C./200 psi/1h                                                                     200         4700     90 C                                     350° C./200 psi/1h                                                                     232         4000     100 C                                    ______________________________________                                        0.85 3,4'-ODA/0.15 DPEB/BPDA/PEPA (Example 8)                                 PASA JELL                                                                     371° C./50 psi/1h                                                                      23          2500     85 A                                     371° C./100 psi/1h                                                                     23          3100     60 A                                     371° C./200 psi/1h                                                                     23          3000     100 A                                    1. 300° C./200 psi/0.5 h                                                               23          4000                                              2. 350° C./200 psi/1.0 h                                               Chromic Acid Anod. (5V)                                                       350° C./200 psi/1h                                                                     200         5000     80 A                                     ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        PRELIMINARY COMPOSITE PROPERTIES.sup.1                                        Imide                           Test                                          Oligomer.sup.2                                                                       Property      Layup      Temp., °C.                                                                     Value                                 ______________________________________                                        2      Flexural Strength, ksi                                                                      Unidirectional                                                                           23      260.3                                                                 177     219.4                                        Flexural Modulus, Msi    23      21.5                                                                  177     20.6                                  2      Open Hole     (42/50/8)  23      57.5                                         Compression, ksi         177 (wet)                                                                             44.6                                  2      Compression (IITRI)                                                                         Unidirectional                                                                           23      232                                          Strength, ksi            177     224                                          Modulus, Msi             23      23.1                                                                  177     22.0                                  2      Tensile Strength, ksi                                                                       Unidirectional                                                                           23      358.8                                        Tensile Modulus, Msi     23      23.7                                         Poission's Ratio         23      0.33                                  2      Short Beam Shear                                                                            Unidirectional                                                                           23      13.5                                         Strength, ksi            150     11.2                                                                  177     10.6                                                                  204     8.8                                   8      Flexural Strength, ksi                                                                      Unidirectional                                                                           23      233.5                                                                 177     190.3                                 8      Flexural Modulus, msi                                                                       Unidirectional                                                                           23      21.08                                                                 177     18.73                                 ______________________________________                                         .sup.1 Composite cured 1h at 371° C./200 psi, solution coated IM7      carbon graphite fibers                                                        .sup.2 Number corresponds to Example number.                             

Controlled molecular weight amide acid and imide co-oligomers containingpendent phenylethynyl groups and chain terminated with eithernonreactive or reactive aniline based endcapping agents were preparedaccording to FIG. 3. The chemical structures of these oligomers areindicated below: ##STR11## wherein Ar is a member selected from thegroup consisting of: ##STR12## wherein Y is a bond or Y is a radicalselected from the group consisting of:

O, CO, SO₂, C(CF₃)₂, isophthalpyl, terephthaloyl, 1,3-diphenoxy and1,4-diphenoxy.

wherein Ar' is a member selected from the group consisting of: ##STR13##wherein the catenation is selected from the group consisting of 2,2';2,3'; 2,4'; 3,3'; 3,4'; and 4,4' and X is a bond or X is a radicalselected from the group consisting of: ##STR14## wherein Z is a radicalselected from the group consisting of: H, ##STR15## wherein R is aradical selected from the group consisting of: ##STR16## wherein theamount of diamine containing pendent phenylethynyl groups ranges from1-99 mole %.

The best results were obtained from example 6. Polymer characterizationis presented in Table 1.

Controlled molecular weight amide acid and imide oligomers containingpendent phenylethynyl groups and chain terminated with eithernonreactive or reactive phthalic anhydride based endcapping agents wereprepared according to FIG. 4.

The chemical structures of these oligomers are indicated below:##STR17## wherein Ar is a member selected from the group consisting of:##STR18## wherein Y is a bond or Y is a radical selected from the groupconsisting of:

O, CO, SO₂, C(CF₃)₂, isophthalpyl, terephthaloyl, 1,3-diphenoxy and1,4-diphenoxy.

wherein W is a radical selected from the group consisting of: H,##STR19## wherein R is a radical selected from the group consisting of:##STR20##

The best results were obtained with example 17. Polymer characterizationis presented in Table 1.

Controlled molecular weight amide acid and imide oligomers containingpendent phenylethynyl groups and chain terminated with eithernonreactive or reactive aniline based endcapping agents were preparedaccording to FIG. 5. The chemical structures of these oligomers areindicated below: ##STR21## wherein Ar is a member selected from thegroup consisting of: ##STR22## wherein Y is a bond or Y is a radicalselected from the group consisting of:

O, CO, SO₂, C(CF₃)₂, isophthalpyl, terephthaloyl, 1,3-diphenoxy and1,4-diphenoxy.

wherein Ar' is a member selected from the group consisting of: ##STR23##wherein Z is a radical selected from the group consisting of: H,##STR24## wherein R is a radical selected from the group consisting of:##STR25## The best results were obtained with example 16. Polymercharacterization is presented in Table 1.

Unendcapped, uncontrolled molecular weight poly(amide acid)s andpolyimides containing pendent phenylethynyl groups were preparedaccording to FIG. 6. The chemical structures of the polymers areindicated below: ##STR26## wherein Ar is a member selected from thegroup consisting of: ##STR27## wherein Y is a bond or Y is a radicalselected from the group consisting of:

O, CO, SO₂, C(CF₃)₂, isophthalpyl, terephthaloyl, 1,3-diphenoxy and1,4-diphenoxy.

wherein R is a radical selected from the group consisting of: ##STR28##

The best results were obtained from example 1. Polymer characterizationis presented in Table 1.

Having generally described the invention, a more complete understandingthereof can be obtained by reference to the following examples which areprovided herein for purposes of illustration only and do not limit theinvention.

Diamine Synthesis

The following example illustrates the reaction sequence in FIG. 1 forthe preparation of the diamine,3,5-diamino-4'-phenylethynylbenzophenone. ##STR29##3,5-Dinitro-4'-bromobenzophenone

To a flame dried 3 necked 3 L round bottom flask equipped with nitrogeninlet, thermometer, mechanical stirrer, condenser and acid trap wascharged 3,5-dinitrobenzoyl chloride (99.00 g, 0.429 mol) andbromobenzene (2000 mL). Anhydrous aluminum chloride (73.40 g, 0.550 mol)was added as a powder in several portions over a 40 minute period atambient temperature. Once the addition of aluminum chloride wascomplete, the temperature was increased to ˜65° C. and maintained for˜24 h. The solution was cooled to ambient temperature and added to arapidly stirred acidic solution (hydrochloric acid 500 mL and 6600 mLdistilled water/ice). A yellow tacky solid separated from solution andwas recovered by vacuum filtration. The tacky solid was washed withmethanol, recovered by vacuum filtration and dried at 100° C. for 2 h inflowing air to afford 107.60 g (71%) of a yellow solid. The crude solidwas recrystallized from toluene to afford 90.1 g (60%) of a yellowcrystalline solid, mp (DSC, 10° C./min)=179° C. Anal. calcd. for C₁₃ H₇N₂ O₅ Br: C, 44.47%; H, 2.00%; N, 7.98%; Br, 22.75%; Found: C, 44.26%;H, 1.75%; N 8.0%; Br, 22.98%. ##STR30##3,5-Dinitro-4'-phenylethynylbenzophenone

To a flame dried 3 necked 2 L round bottom flask equipped with nitrogeninlet, thermometer, mechanical stirrer and condenser was charged3,5-dinitro-4'-bromobenzophenone (101.0 g, 0.288 mol), triethylamine (1L), cuprous iodide (0.24 g, 1.26 mmol), triphenylphosphine (1.50 g, 5.72mmol), bis(triphenylphosphine)palladium dichloride (0.30 g, 0.4274 mmol)and phenylacetylene (32.32 g, 0.316 mol). The temperature was increasedto 85° C. and maintained for ˜12 h. After ˜2 hr, the solid precipitatewas very thick making stirring difficult. The mixture was cooled toambient temperature and the crude solid recovered by vacuum filtration.The solid was washed successively in acidic water, distilled water anddried at 105° C. in a forced air oven for ˜17 h to afford 104 g (97%) ofa dark brown powder, (DSC, 10° C./min) very small peak at 156° C. and abroad peak centered at 181° C. The onset of the exothermic peak maximumwas 403° C. and 423° C., respectively. Recrystallization from toluene (1L) afforded a first crop of yellow/orange crystals (66 g, 63%) with asharp melting point centered at 188° C. A second crop of crystals (15.0g) was obtained after reducing the volume of the filtrate, mp 188° C.Final yield was 83.5 g (78%). Anal. calcd. for C₂₁ H₁₂ N₂ O₅ : C,67.73%; H, 3.25%; N, 7.52%; Found: C, 67.64%; H, 3.55%; N 7.67%.##STR31##

3,5-Diamino-4'-phenylethynylbenzophenone

To a 1 L Erlenmeyer flask equipped with a magnetic stirrer was charged3,5-dinitro-4'-phenylethynylbenzophenone (19.6 g, 0.053 mol) and1,4-dioxane (450 mL). The orange solution was cooled to ˜10°-15° C. bymeans of an ice bath. A cooled solution (˜10° C.) of stannous chloridedihydrate (78.4 g, 0.35 mol) in concentrated hydrochloric acid (300 mL)was added dropwise while maintaining the temperature between 10°-20° C.After the addition, the ice bath was removed and the reaction mixtureallowed to warm to room temperature. The mixture was stirred at roomtemperature for ˜16 h. During this time the product precipitated fromsolution. The solid was collected, placed in distilled water andneutralized with aqueous ammonium hydroxide. The crude material wascollected by filtration, washed in water and dried at 65° C. for 1 h inflowing air to afford 16.0 g (98%) of a crude solid. The crude productwas recrystallized form toluene to afford 13.1 g (80%) of a yellowpowder, mp (DSC, 10° C./min) 156° C. Anal. calcd. for C₂₁ H₁₆ N₂ O: C,80.74%; H, 5.16%; N, 8.97%; Found: C, 80.73%; H, 5.10%; N 8.98%.

EXAMPLE 1 1.0 3,5-Diamino-4'-phenylethynylbenzophenone and 1.04,4'-Oxydiphthalic Anhydride with no Endcapping Agent

The following example illustrates the reaction sequence in FIG. 6 forthe preparation of the uncontrolled high molecular weight PEPI where Ris a 4-benzoyl group and Ar is 3,3',4,4'-diphenylether and the monomerstoichiometry is 1.0 to 1.0. ##STR32##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,5-diamino-4'-phenylethynylbenzophenone (2.0069 g, 0.0064 mol) and 6 mLof N,N-dimethylacetamide (DMAc). After dissolution, 4,4'-oxydiphthalicanhydride (1.9931 g, 0.0064 mol) and DMAc (10 mL) were added to give afinal concentration of 20.0% (w/w) solution. The reaction was stirred atroom temperature for 24 h under nitrogen. The inherent viscosity of thepoly(amide acid) solution (0.5% in DMAc at 25° C.) was 0.85 dL/g.Approximately 7 g of poly(amide acid) solution was used to cast anunoriented thin film. Toluene (30 mL) was added to the remainingpoly(amide acid) solution and the temperature increased and maintainedat ˜150° C. for ˜16 h under a nitrogen atmosphere. As cyclodehydrationto the imide occurred, the polymer precipitated. The polyimide powderwas washed in hot water, warm methanol, and dried under vacuum at 230°C. for 4 h to provide a tan powder (2.3 g,43% yield). The T_(g) of theuncured as-isolated polymer (DSC, 20° C./min) was 273° C. and theexothermic onset and peak occurred at 340° C. and 419° C., respectively.The T_(g) of the cured polymer (cure conditions: 350° C./1 h/sealedpan)was not detectable by DSC. Unoriented thin film cast from the DMAcsolution of the poly(amide acid) and cured at 100°, 225°, and 350° C.for 1 h each in flowing air did not exhibit a T_(g) by DSC. The T_(g) bythermomechanical analysis (TMA) at a heating rate of 5° C./min was 300°C. Polymer characterization is presented in Table 1.

EXAMPLE 2 0.85:0.15 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.90933,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.07 mole %Stoichiometric offset and 18.14 mole % Phthalic Anhydride (Calculated(M)_(n) =5000 g/mol

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a hydrogen atom. The ratio of diaminesAr':R! is 0.85:0.15. The stoichiometric imbalance is 9.07 mole % and theendcapping reagent is 18.14 mole % of phthalic anhydride. ##STR33##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.7220 g, 0.0186 mol),3,5-diamino-4'-phenylethynylbenzophenone (1.0246 g, 0.0033 mol) and 9 mLN-methyl-2-pyrrolidinone (NMP). After dissolution, a slurry of4,4'-biphenyltetracarboxylic dianhydride. (5.8502 g, 0.0199 mol), andphthalic anhydride (0.5924 g, 0.0040 mol) in 10 mL of NMP was added andwashed in with an additional 7 mL of NMP to afford a 30.0% (w/w)solution. The reaction was stirred at room temperature for 24 h undernitrogen. The inherent viscosity of the amide acid oligomeric solution(0.5% in NMP at 25° C.) was 0.33 dL/g. Approximately 11 g of amide acidoligomeric solution was used to cast an unoriented thin film. Thereaction vessel was fitted with a moisture trap and toluene (40 mL) wasadded to the remaining amide acid oligomeric solution and thetemperature increased and maintained at ˜180° C. for ˜16 h under anitrogen atmosphere. As cyclodehydration to the imide occurred, theoligomer began to precipitate. The oligomer was washed in hot water,warm methanol, and dried under vacuum at 230° C. for 4 h to provide abrown powder (6.9 g, 66% yield). The T_(g) of the uncured as-isolatedoligomer (DSC, 20° C./min) was 240° C. with a very slight T_(m) at 325°C. and the exothermic onset and peak occurred at 340° C. and 423° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was not detected by DSC. Unoriented thin films cast from aNMP solution of the amide acid oligomer cured at 100°, 225°, and 350° C.for 1 h each in flowing air gave tensile strength, tensile modulus, andelongation at 23° C. of 21.8 ksi, 600 ksi, and 4% and at 177° C. of 14.0ksi, 411 ksi, and 5% and at 200° C. of 12 ksi, 372 ksi, and 6%,respectively. The T_(g) of the cured film was 279° C. A samplecompression molded at 300° C./200 psi/0.5 h then 350° C./200 psi/1 h hada G_(IC) (critical strain energy release rate) of 6.2 in lb/in² and aT_(g) of 280° C. The titanium (Ti) to Ti tensile shear properties bondedat 300° C./200 psi/0.5 h then 350° C./200 psi/1 h were 3900 at 23° C.and 4100 at 177° C. Flexural properties of composite panels preparedfrom prepreg of example 2 on IM-7 fiber processed at 250° C./50 psi/1 hthen 371° C./200 psi/1 h with a unidirectional lay-up gave flexuralstrength and flexural modulus at 23° C. of 260.3 ksi and 21.52 Msi andat 177° C. of 219.4 ksi and 20.58 Msi, respectively. Polymercharacterization is presented in Table 1, thin film mechanicalproperties are presented in Table 2, adhesive properties are presentedin Table 3 and carbon fiber reinforced composite properties arepresented in Table 4.

EXAMPLE 3 0.85:0.15 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.9763,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 2.4 mole %Stoichiometric offset and 4.8 mole % Phthalic Anhydride (Calculated(M)_(n) =20,000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a hydrogen atom. The ratio of diaminesAr':R! is 0.85:0.15. The-stoichiometric imbalance is 2.4 mole % and theendcapping reagent is 4.8 mole % of phthalic anhydride. ##STR34##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (2.8765 g, 0.01436 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.7919 g, 0.00253 mol) and10.1 mL N-methyl-2-pyrrolidinone (NMP). After dissolution,4,4'-biphenyltetracarboxylic dianhydride, (4.8530 g, 0.0165 mol), andphthalic anhydride (0.1201 g, 0.00081 mol). NMP (10.0 mL) was used towash in the solid to afford a 30.0% (w/w) solution. The reaction wasstirred at room temperature for 24 h under nitrogen. The inherentviscosity of the amide acid oligomeric solution (0.5% in NMP at 25° C.)was 0.645 dL/g. Approximately 7.1 g of amide acid oligomeric solutionwas used to cast an unoriented thin film. The reaction vessel was fittedwith a moisture trap and toluene (40 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, the oligomer began toprecipitate. The oligomer was washed in hot water, warm methanol, anddried under vacuum at 230° C. for 4 h to provide a brown powder (6.0 g,75% yield). The T_(g) of the uncured as-isolated oligomer (DSC, 20°C./min) was 265° C. and the exothermic onset and peak occurred at 340°C. and 423° C., respectively. The T_(g) of the cured polymer (cureconditions: 350° C./1 h/sealed pan) was 297° C. by DSC. Unoriented thinfilms cast from a NMP solution of the amide acid oligomer cured at 100°,225°, and 350° C. for 1 h each in flowing air gave tensile strength,tensile modulus, and elongation at 23° C. of 16.3 ksi, 473 ksi, and 4%.The T_(g) of the cured film was not detectable by DSC. Polymercharacterization is presented in Table 1.

EXAMPLE 4 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.90933,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.07 mole %Stoichiometric offset and 18.14 mole % Phthalic Anhydride (Calculated(M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a hydrogen atom. The ratio of diaminesAr':R! is 0.90:0.10. The stoichiometric imbalance is 8.97 mole % and theendcapping reagent is 17.94 mole % of phthalic anhydride. ##STR35##

Into a flame dried 100 mL three necked round bottom flask equipped with,nitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (4.8752 g, 0.0243 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.8450 g, 0.0027 mol) and 10mL N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurry of4,4'-biphenyltetracarboxylic dianhydride (7.2451 g, 0.0246 mol) andphthalic anhydride (0.7188 g, 0.0049 mol) in 10 mL of NMP was added andwashed in with an additional 10 mL of NMP to afford a 30.6% (w/w)solution. The reaction was stirred at room temperature for 24 h undernitrogen. The inherent viscosity of the amide acid oligomeric solution(0.5% in NMP at 25° C.) was 0.32 dL/g. Approximately 13 g of amide acidoligomeric solution was used to cast an unoriented thin film. Thereaction vessel was fitted with a moisture trap and toluene (60 mL) wasadded to the remaining amide acid oligomeric solution and thetemperature increased and maintained at ˜180° C. for ˜16 h under anitrogen atmosphere. As cyclodehydration to the imide occurred, theoligomer began to precipitate. The oligomer was washed in hot water,warm methanol, and dried under vacuum at 230° C. for 4 h to provide ayellow powder (8.91 g, 70% yield). The inherent viscosity of the imideoligomer (0.5% in m-cresol at 25° C.) was 0.28 dL/g. The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was 217° C. with a T_(m)at 276° C. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was 255° C. with a T_(m) at 369° C. The T_(g) of the curedfilm was 259° C. with a T_(m) at 367° C. Polymer characterization ispresented in Table 1.

EXAMPLE 5 0.70:0.30 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.90933,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.07 mole %Stoichiometric offset and 18.14 mole % Phthalic Anhydride (Calculated(M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a hydrogen atom. The ratio of diaminesAr':R! is 0.70:0.30. The stoichiometric imbalance is 9.38 mole % and theendcapping reagent is 18.76 mole % of phthalic anhydride. ##STR36##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.5721 g, 0.0178 mol),3,5-diamino-4'-phenylethynylbenzophenone (2.3882 g, 0.0076 mol) and 10mL N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurry of4,4'-biphenyltetracarboxylic dianhydride, (6.7947 g, 0.0231 mol), andphthalic anhydride (0.7081 g, 0.0048 mol) in 10 mL of NMP was added andwashed in with an additional 10 mL of NMP to afford a 30.3% (w/w)solution. The reaction was stirred at room temperature for 24 h undernitrogen. The inherent viscosity of the amide acid oligomeric solution(0.5% in NMP at 25° C.) was 0.31 dL/g. Approximately 11 g of amide acidoligomeric solution was used to cast an unoriented thin film. Thereaction vessel was fitted with a moisture trap and toluene (60 mL) wasadded to the remaining amide acid oligomeric solution and thetemperature increased and maintained at ˜180° C. for ˜16 h under anitrogen atmosphere. As cyclodehydration to the imide occurred, theOligomer began to precipitate. The oligomer was washed in hot water,warm methanol, and dried under vacuum at 230° C. for 4 h to provide abrown powder (8.93 g, 71% yield). The inherent viscosity of the imideoligomer (0.5% in m-cresol at 25° C.) was 0.22 dL/g. The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was 230° C. with T_(m) sat 272° and 286° C. The T_(g) of the cured polymer (cure conditions:350° C./1 h/sealed pan) was 293° C. Unoriented thin films cast from aNMP solution of the amide acid oligomer cured at 100°, 225°, and 350° C.for 1 h each in flowing air gave tensile strength, tensile modulus, andelongation at 23° C. of 23.5 ksi, 563 ksi, and 8%; at 177° C. of 12.7ksi, 370 ksi, and 6% and at 200° C. of 12.2 ksi, 370 ksi, and 9%,respectively. The T_(g) of the cured film was 289° C. Polymercharacterization is presented in Table 1 and thin film mechanicalproperties are presented in Table 2.

EXAMPLE 6 0.85:0.15 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.07 mole %Stoichiometric offset and 18.14 mole %3-Aminophenoxy-4'phenylethynylbenzophenone (Calculated (M)_(n) =5000g/mole)

The following example illustrates the reaction sequence in FIG. 3 forthe preparation of the controlled molecular weight PEPI where Ar is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and Z is a phenoxy-4'-phenylethynylbenzophenone grouplocated in the 3 position. The ratio of diamines Ar':R! is 0.85:0.15.The stoichiometric imbalance is 9.07 mole % and the endcapping reagentis 18.14 mole % of 3-aminophenoxy-4'phenylethynylbenzophenone. ##STR37##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.8826 g, 0.0194 mol),3,5-diamino-4'-phenylethynylbenzophenone (1.0689 g, 0.0034 mol),3-aminophenoxy-4'phenylethynylbenzophenone (1.7723 g, 0.0046 mol) and 10mL (39.4% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, aslurry of 3,3',4,4'-biphenyltetracarboxylic dianhydride (7.3809 g,0.0251 mol) in 10 mL (41.7% w/w) of NMP was added and washed in with anadditional 11 mL of NMP to afford a 30.6% (w/w) solution. The reactionwas stirred at room temperature for 24 h under nitrogen. The inherentviscosity of the amide acid oligomeric solution (0.5% in NMP at 25° C.)was 0.26 dL/g. Approximately 10.85 g of amide acid oligomeric solutionwas used to cast an unoriented thin film. Toluene (60 mL) was added tothe remaining amide acid oligomeric solution and the temperatureincreased and maintained at ˜180° C. for ˜16 h under a nitrogenatmosphere. As cyclodehydration to the imide occurred, a precipitateformed. The mixture was cooled, the oligomer was washed in hot water,warm methanol, and dried under vacuum at 220° C. for 1.5 h to provide atan powder (10.06 g, 76% yield). The inherent viscosity of the imideoligomer (0.5% in m-cresol at 25° C.) was 0.24 dL/g. The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was 209° C. with a T_(m)at 278° C. and the exothermic onset and peak occurred at 359° C. and406° C., respectively. The T_(g) of the cured polymer (cure conditions:350° C./1 h/sealed pan) was 300° C. An unoriented thin films cast from aNMP solution of the amide acid oligomer cured at 100°, 225°, and 350° C.for 1 h each in flowing air was phase separated. The T_(g) of the curedfilm was 299° C. Polymer characterization is presented in Table 1.

EXAMPLE 7 0.75:0.15:0.10 3,4'-Oxydianiline,1,3-bis(3-aminophenoxy)benzene and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.22 mole %Stoichiometric offset and 18.44 mole % 4-Phenylethynylphthalic Anhydride(Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' (1) is3,4'-diphenylether and Ar' (2) is 1,3-phenoxyphenyl and R is a 4-benzoylgroup and Ar is 3,3',4,4'-biphenyl and W is a phenylethynyl grouplocated in the 4 position. The ratio of diamines Ar' (1):Ar' (2):R! is0.75:0.15:0.10. The stoichiometric imbalance is 9.22 mole % and theendcapping reagent is 18.44 mole % of 4-phenylethynylphthalic anhydride.##STR38##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (2.9030 g, 0.0145 mol), 1,3-bis(3-aminophenoxy)benzene(0.8476 g, 0.0029 mol), 3,5-diamino-4'-phenylethynylbenzophenone (0.6038g, 0.0019 mol) and 20 mL (17.4% w/w) of m-cresol. After dissolution, aslurry of 3,3',4,4'-biphenyltetracarboxylic dianhydride (5.1627 g,0.0175 mol) and 4-phenylethynylphthalic anhydride (0.8848 g, 0.0036 mol)in 20 mL (22.6% w/w) of m-cresol was added and washed in with anadditional 15 mL of m-cresol to afford a 15.5% (w/w) solution. Thereaction mixture was stirred at room temperature for ˜16 h. The tanopaque solution was warmed to ˜100° C. for 0.75 h to effect dissolutionof the oligomer. The solution was cooled to ˜50° C. and isoquinoline (9drops) was added to the mixture. The temperature was increased andmaintained at ˜205° C. for ˜6.5 h under a nitrogen atmosphere. Themixture was cooled, the oligomer precipitated in methanol, washed inwarm methanol, and dried at 230° C. under vacuum for 1 h to provide alight yellow powder (9.7 g, ˜100% yield). The inherent viscosity of a0.5% (w/v) solution of the imide oligomer in m-cresol at 25° C. was 0.26dL/g. The T_(g) of the uncured as-isolated oligomer (DSC, 20° C./min)was 226° C. with an exothermic onset and peak at 359° C. and 425° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was 286° C. Unoriented thin films cast from a m-cresolsolution of the amide acid oligomer cured at 100°, 225°, and 350° C. for1 h each in flowing air gave tensile strength, tensile modulus, andelongation at 23° C. of 18.9 ksi, 495 ksi, and 12%; at 177° C. of 10.8ksi, 301 ksi, and 34%; and at 200° C. of 9.2 ksi, 276 ksi, and 25%,respectively. The T_(g) of the cured film was 290° C. A samplecompression molded at 275° C./200 psi/0.5 h then 350° C./200 psi/1 h hada G_(IC) (critical strain energy release rate) of 10.3 in lb/in².Polymer characterization is presented in Table 1 and thin filmmechanical properties are presented in Table 2.

EXAMPLE 8 0.85:0.15 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.07 mole %Stoichiometric offset and 18.14 mole % 4-Phenylethynylphthalic Anhydride(Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a phenylethynyl group located in the 4position. The ratio of diamines Ar':R! is 0.85:0.15. The stoichiometricimbalance is 9.07 mole % and the endcapping reagent is 18.14 mole % of4-phenylethynylphthalic anhydride. ##STR39##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.722 g, 0.0186 mol),3,5-diamino-4'-phenylethynylbenzophenone (1.0246 g, 0.0033 mol) and 8 mL(36.5% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurryof 3,3',4,4'-biphenyltetracarboxylic dianhydride (5.8502 g, 0.0199 mol)and 4-phenylethynylphthalic anhydride (0.9847 g, 0.0040 mol) in 9 mL(42.4% w/w) of NMP was added and washed in with an additional 9 mL ofNMP to afford a 30.1% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.32 dL/g.Approximately 10 g of amide acid oligomeric solution was used to cast anunoriented thin film. Toluene (60 mL) was added to the remaining amideacid oligomeric solution and the temperature increased and maintained at˜180° C. for ˜16 h under a nitrogen atmosphere. As cyclodehydration tothe imide occurred, a precipitate formed. The mixture was cooled, theoligomer was washed in hot water, warm methanol, and dried under vacuumat 220° C. for 1.5 h to provide a tan powder (7.94 g, 74% yield). TheT_(g) of the uncured as-isolated oligomer (DSC, 20° C./min) was 226° C.with a T_(m) at 283° C. and the exothermic onset and peak occurred at348° C. and 406° C., respectively. The inherent viscosity of the imideoligomer (0.5% in m-cresol at 25° C.) was 0.28 dL/g. The T_(g) of thecured polymer (cure conditions: 350° C./1 h/sealed pan) was 313° C.Unoriented thin films cast from a NMP solution of the amide acidoligomer cured at 100°, 225°, and 350° C. for 1 h each in flowing airgave tensile strength, tensile modulus, and elongation at 23° C. of 20.2ksi, 497 ksi, and 10%; at 177° C. of 11.4 ksi, 322 ksi, and 9%, and at200° C. of 9.9 ksi, 267 ksi, and 17%, respectively. The T_(g) of thecured film was 318° C. A sample compression molded at 300° C./200psi/0.5 h then 371° C./200 psi/1 h had a G_(IC) (critical strain energyrelease rate) of 2.9 in lb/in² and a T_(g) of 312° C. Flexuralproperties of composite panels prepared from prepreg of example 8 onIM-7 fiber processed at 250° C./50 psi/1 h then 371° C./200 psi/1 h witha unidirectional lay-up gave flexural strength and flexural modulus at23° C. of 233.5 ksi and 21.08 Msi and at 177° C. of 190.3 ksi and 18.73Msi, respectively. Polymer characterization is presented in Table 1,thin film mechanical properties are presented in Table 2, adhesiveproperties are presented in Table 3 and carbon fiber reinforcedcomposite properties are presented in Table 4.

EXAMPLE 9 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 8.97 mole %Stoichiometric offset and 17.94 mole % 4-Phenylethynylphthalic Anhydride(Calculated(M_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-biphenyl and W is a phenylethynyl group located in the 4position. The ratio of diamines Ar' (1):Ar' (2)! is 0.90:0.10. Thestoichiometric imbalance is 8.97 mole % and the endcapping reagent is17.94 mole of 4-phenylethynylphthalic anhydride. ##STR40##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.9211 g, 0.0196 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.6797 g, 0.0022 mol) and 8 mL(35.8% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurryof 3,3',4,4'-biphenyltetracarboxylic dianhydride (5.8275 g, 0.0198 mol)and 4-phenylethynylphthalic anhydride (0.9690 g, 0.0040 mol) in 8 mL(45.1% w/w) of NMP was added and washed in with an additional 9 mL ofNMP to afford a 30.6% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.21 dL/g.Approximately 10.5 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, a precipitate formed. Themixture was cooled, the oligomer was washed in hot water, warm methanol,and dried under vacuum at 220° C. for 1.5 h to provide a tan powder(7.00 g, 66% yield). The inherent viscosity of the imide oligomer (0.5%in m-cresol at 25° C.) was 0.41 dL/g. The T_(g) of the uncuredas-isolated oligomer (DSC, 20° C./min) was 223° C. with a T_(m) at 274°C. and the exothermic onset and peak occurred at 350° C. and 412° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was 310° C. Unoriented thin films cast from a NMP solutionof the amide acid oligomer cured at 100°, 225°, and 350° C. for 1 h eachin flowing air gave tensile strength, tensile modulus, and elongation at23° C. of 20.5 ksi, 495 ksi, and 20%; at 177° C. of 12.1 ksi, 296 ksi,and 27% and at 200° C. of 10.7 ksi, 299 ksi, and 30%, respectively. TheT_(g) of the cured film was 306° C. Polymer characterization ispresented in Table 1 and thin film mechanical properties are presentedin Table 2.

EXAMPLE 10 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Benzophenonetetracarboxylic Dianhydride, Using 9.48 mole %Stoichiometric offset and 18.96 mole % 4-Phenylethynylphthalic(Anhydride (Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-benzophenone and W is a phenylethynyl group located in the 4position. The ratio of diamines Ar':R! is 0.90:0.10. The stoichiometricimbalance is 9.48 mole % and the endcapping reagent is 18.96 mole % of4-phenylethynylphthalic anhydride. ##STR41##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.9229 g, 0.0196 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.6800 g, 0.0022 mol) and 10mL (30.8% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, aslurry of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (6.3494 g,0.0197 mol) and 4-phenylethynylphthalic anhydride (1.0245 g, 0.0041 mol)in 8 mL (47.2% w/w) of NMP was added and washed in with an additional 9mL of NMP to afford a 30.0% (w/w) solution. The reaction was stirred atroom temperature for 24 h under nitrogen. The inherent viscosity of theamide acid oligomeric solution (0.5% in NMP at 25° C.) was 0.28 dL/g.Approximately 10.5 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, a precipitate formed. Themixture was cooled, the oligomer was washed in hot water, warm methanol,and dried under vacuum at 220° C. for 1.5 h to provide a tan powder(7.43 g, 66% yield). The T_(g) of the uncured as isolated oligomer (DSC,20° C./min) was 269° C. and the exothermic onset and peak occurred at352° C. and 399° C., respectively. The T_(g) of the cured polymer (cureconditions: 350° C./1 h/sealed pan) was 296° C. An unoriented thin filmscast from a NMP solution of the amide acid oligomer cured at 100°, 225°,and 350° C. for 1 h each in flowing air was brittle and broke on theplate. The T_(g) of the cured film was 296° C. Polymer characterizationis presented in Table 1.

EXAMPLE 11 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and Pyromellitic Dianhydride,Using 7.57 mole % Stoichiometric offset and 15.14 mole %4-Phenylethynylphthalic Anhydride (Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is1,2,4,5-tetrasubstituted benzene, and W is a phenylethynyl group locatedin the 4 position. The ratio of diamines Ar':R! is 0.90:0.10. Thestoichiometric imbalance is 9.48 mole % and the endcapping reagent is18.96 mole % of 4-phenylethynylphthalic anhydride. ##STR42##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.7846 g, 0.0189 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.6560 g, 0.0021 mol) and 11.0mL N-methyl-2-pyrrolidinone (NMP). After dissolution, pyromelliticdianhydride, (4.2337 g, 0.01941 mol), and 4-phenylethynylphthalicanhydride (0.7893 g, 0.00318 mol). NMP (10.0 mL) was used to wash in thesolid to afford a 30.0% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.36 dL/g.Approximately 7.9 g of amide acid oligomeric solution was used to castan unoriented thin film. The reaction vessel was fitted with a moisturetrap and toluene (40 mL) was added to the remaining amide acidoligomeric solution and the temperature increased and maintained at˜180° C. for ˜16 h under a nitrogen atmosphere. As cyclodehydration tothe imide occurred, the oligomer began to precipitate. The oligomer waswashed in hot water, warm methanol, and dried under vacuum at 230° C.for 4 h to provide a brown powder (6.3 g, 76% yield). The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was not detected by DSCand the exothermic onset and peak occurred at 340° C. and 423° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was not detectable by DSC. Unoriented thin films cast froma NMP solution of the amide acid oligomer cured at 100°, 225°, and 350°C. for 1 h each in flowing air were brittle and cracked up into tinypieces. The T_(g) of the cured film was not detectable by DSC. Polymercharacterization is presented in Table 1.

EXAMPLE 12 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 4,4'-OxydiphthalicDianhydride, Using 9.3 mole % Stoichiometric offset and 18.6 mole %4-Phenylethynylphthalic Anhydride (Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group and Ar is3,3',4,4'-diphenylether and W is a phenylethynyl group located in the 4position. The ratio of diamines Ar':R! is 0.90:0.10. The stoichiometricimbalance is 9.3 mole % and the endcapping reagent is 18.6 mole % of4-phenylethynylphthalic anhydride. ##STR43##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (3.2439 g, 0.0162 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.5623 g, 0.0018 mol) and 12.0mL N-methyl-2-pyrrolidine (NMP). After dissolution, 4,4'-oxydiphthalicdianhydride, (5.0645 g, 0.0163 mol), and 4-phenylethynylphthalicanhydride (0.8311 g, 0.00334 mol). NMP (10.0 mL) was used to wash in thesolid to afford a 30.0% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.30 dL/g.Approximately 6.4 g of amide acid oligomeric solution was used to castan unoriented thin film. The reaction vessel was fitted with a moisturetrap and toluene (40 mL) was added to the remaining amide acidoligomeric solution and the temperature increased and maintained at˜180° C. for ˜16 h under a nitrogen atmosphere. As cyclodehydration tothe imide occurred, the oligomer began to precipitate. The oligomer waswashed in hot water, warm methanol, and dried under vacuum at 230° C.for 4 h to provide a brown powder (6.6 g, 75% yield). The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was ˜240° C. by DSC andthe exothermic onset and peak occurred at 340° C. and 423° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was 260° C. by DSC. Polymer characterization is presentedin Table 1.

EXAMPLE 13 0.70:0.15:0.15 3,4'-Oxydianiline,1,3-bis(3-aminophenoxy)benzene and3,5-Diamino-4'-phenylethynylbenzophenone, and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 9.33 mole %Stoichiometric offset and 18.66 mole % 4-Phenylethynylphthalic Anhydride(Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' (1) is3,4'-diphenylether and Ar' (2) is 1,3-diphenoxyphenyl and R is a4-benzoyl group and Ar is 3,3',4,4'-biphenyl and W is a phenylethynylgroup located in the 4 position. The ratio of diamines Ar' (1):Ar'(2):R! is 0.70:0.15:0.15. The stoichiometric imbalance is 9.33 mole %and the endcapping reagent is 18.66 mole % of 4-phenylethynylphthalicanhydride. ##STR44## Into a flame dried 100 mL three necked round bottomflask equipped with nitrogen inlet, mechanical stirrer, and drying tubewere placed 3,4'-oxydianiline (3.3565 g, 0.0168 mol),1,3-bis(3-aminophenoxy)benzene (1.0501 g, 0.0036 mol),3,5-diamino-4'-phenylethynylbenzophenone (1.1220 g, 0.0036 mol) and 10mL of N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurry of3,3',4,4'-biphenyltetracarboxylic dianhydride (6.3881 g, 0.0217 mol) and4-phenylethynyl phthalic anhydride (1.1092 g, 0.0045 mol)in 9 mL (22.6%w/w) of NMP was added and washed in with an additional 10 mL of NMP toafford a 30.28% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.29 dL/g.Approximately 12.6 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, the oligomer precipitated insolution. The oligomer was washed in hot water, warm methanol, and driedunder vacuum at 230° C. for 2 h to provide a brown powder (8.07 g, 66%yield). The inherent viscosity of the imide oligomer (0.5% in m-cresolat 25° C.) was 0.32 dL/g. The T_(g) of the uncured as-isolated oligomer(DSC, 20° C./min) was 224° C. with a T_(m) at 284° C. and the exothermiconset and peak occurred at 363° C. and 416° C., respectively. The T_(g)of the cured polymer (cure conditions: 350° C./1 h/sealed pan) was 289°C. Unoriented thin films cast from a NMP solution of the amide acidoligomer cured at 100°, 225°, and 350° C. for 1 h each in flowing airgave tensile strength, tensile modulus, and elongation at 23° C. of 20.4ksi, 492 ksi, and 15%; at 177° C. of 11.2 ksi, 307 ksi, and 24% and at200° C. of 9.9 ksi, 285 ksi, and 28%, respectively. The T_(g) of thecured film was 301° C. A sample compression molded at 371° C./200 psi/1h had a G_(IC) (critical strain energy release rate) of 6.2 in lb/in².Polymer characterization is presented in Table 1, thin film mechanicalproperties are presented in Table 2 and adhesive properties arepresented in Table 3.

Mixtures of dianhydrides were used to alter properties as illustrated inExamples 14 and 15.

EXAMPLE 14 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.85:0.153,3',4,4'-Benzophenonetetracarboxylic Dianhydride and 4,4'-OxydiphthalicAnhydride, Using 9.02 mole % Stoichiometric offset and 18.04 mole %4-Phenylethynylphthalic Anhydride (Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group; Ar (1) is3,3',4,4'-diphenylether and Ar (2) is 3,3',4,4'-benzophenone and W is aphenylethynyl group located in the 4 position. The ratio of diamines Ar'(1):Ar' (2)! is 0.90:0.10 and the ratio of dianhydrides Ar (1):Ar (2)!is 0.15:0.85. The stoichiometric imbalance is 9.02 mole % and theendcapping reagent is 18.04 mole % of 4-phenylethynylphthalic anhydride##STR45##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (4.6046 g, 0.0230 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.7981 g, 0.0026 mol) and 9 mL(36.8% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, a slurryof 3,3',4,4'-biphenyltetracarboxylic dianhydride (5.8134 g, 0.0198 mol),4,4'-oxydiphthalic anhydride (1.0817 g, 0.0035 mol) and4-phenylethynylphthalic anhydride (1.1436 g, 0.0046 mol)in 10 mL (43.4%w/w) of NMP was added and washed in with an additional 11 mL of NMP toafford a 30.3% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.35 dL/g.Approximately 10.6 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, the oligomer remained insolution. As the mixture was cooled, a precipitate formed. The oligomerwas washed in hot water, warm methanol, and dried under vacuum at 220°C. for 1.5 h to provide a brown powder (9.47 g, 76% yield). The inherentviscosity of the imide oligomer (0.5% in m-cresol at 25° C.) was 0.26dL/g. The T_(g) of the uncured as-isolated oligomer (DSC, 20° C./min)was not detected with T_(m) s at 243° and 262° C. and the exothermiconset and peak occurred at 320° C. and 391° C., respectively. The T_(g)of the cured polymer (cure conditions: 350° C./1 h/sealed pan) was 310°C. Unoriented thin films cast from a NMP solution of the amide acidoligomer cured at 100°, 225°, and 350° C. for 1 h each in flowing airgave tensile strength, tensile modulus, and elongation at 23° C. of 19.8ksi, 489 ksi, and 12%; at 177° C. of 10.7 ksi, 290 ksi, and 11% and at200° C. of 10.3 ksi, 329 ksi, and 11%, respectively. The T_(g) of thecured film was 294° C. Polymer characterization is presented in Table 1and thin film mechanical properties are presented in Table 2.

EXAMPLE 15 0.90:0.10 3,4'-Oxydianiline and3,5-Diamino-4'-phenylethynylbenzophenone, and 0.70:0.303,3',4,4'-Benzophenonetetracarboxylic Dianhydride and 4,4'-OxydiphthalicAnhydride, Using 9.06 mole % Stoichiometric offset and 18.12 mole %4-Phenylethynylphthalic Anhydride (Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in FIG. 2 forthe preparation of the controlled molecular weight PEPI where Ar' is3,4'-diphenylether and R is a 4-benzoyl group; Ar (1) is3,3',4,4'-diphenylether and Ar (2) is 3,3',4,4'-biphenyl and W is aphenylethynyl group located in the 4 position. The ratio of diamines Ar'(1):Ar' (2)! is 0.90:0.10 and the ratio of dianhydrides Ar (1):Ar (2)!is 0.30:0.70. The stoichiometric imbalance is 9.06 mole % and theendcapping reagent is 18.12 mole % of 4-phenylethynylphthalic anhydride##STR46##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,4'-oxydianiline (4.6301 g, 0.0231 mol),3,5-diamino-4'-phenylethynylbenzophenone (0.8025 g, 0.0026 mol) and 10mL (34.5% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, aslurry of 3,3',4,4'-biphenyltetracarboxylic dianhydride (4.8118 g,0.0164 mol), 4,4'-oxydiphthalic anhydride (2.1744 g, 0.0070 mol) and4-phenylethynylphthalic anhydride (1.1556 g, 0.0047 mol) in 10 mL (44.1%w/w) of NMP was added and washed in with an additional 10 mL of NMP toafford a 30.5% (w/w) solution. The reaction was stirred at roomtemperature for 24 h under nitrogen. The inherent viscosity of the amideacid oligomeric solution (0.5% in NMP at 25° C.) was 0.33 dL/g.Approximately 10.9 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, the oligomer remained insolution. As the mixture was cooled, a precipitate formed, The oligomerwas washed in hot water, warm methanol, and dried under vacuum at 230°C. for 4 h to provide a brown powder (7.98 g, 63% yield). The inherentviscosity of the imide oligomer (0.5% in m-cresol at 25° C.) was 0.31dL/g. The T_(g) Of the uncured as-isolated oligomer (DSC, 20° C./min)was 227° C. with a T_(m) at 260° C. and the exothermic onset and peakoccurred at 340° C. and 419° C., respectively. The T_(g) of the curedpolymer (cure conditions: 350° C./1 h/sealed pan) was 299° C. Unorientedthin films cast from a NMP solution of the amide acid oligomer cured at100°, 225°, and 350° C. for 1 h each in flowing air gave tensilestrength, tensile modulus, and elongation at 23° C. of 19.5 ksi, 457ksi, and 16%; at 177° C. of 10.1 ksi, 291 ksi, and 20% and at 200° C. of9.2 ksi, 299 ksi, and 12%, respectively. The T_(g) of the cured film was296° C. Polymer characterization is presented in Table 1 and thin filmmechanical properties are presented in Table 2.

EXAMPLE 16 3,5-Diamino-4'-phenylethynylbenzophenone and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 10.80 mole %Stoichiometric offset and 21.60 mole %3-Aminophenoxy-4'phenylethynylbenzophenone (Calculated (M)_(n) =5000g/mole)

The following example illustrates the reaction sequence in FIG. 5 forthe preparation of the controlled molecular weight PEPI where Ar is1,3-diphenylene, R is a 4-benzoyl group and Ar is 3,3',4,4'-biphenyl andZ is a phenoxy-4'-phenylethynylbenzophenone group located in the 3position. The stoichiometric imbalance is 10.80 mole % and theendcapping reagent is 21.60 mole % of3-aminophenoxy-4'phenylethynylbenzophenone. ##STR47##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,5-diamino-4'-phenylethynylbenzophenone (2.5741 g, 0.0082 mol) and3-aminophenoxy-4'-phenylethynylbenzophenone (0.7771 g, 0.0020 mol) and 6mL (35.1% w/w) N-methyl-2-pyrrolidinone (NMP). After dissolution, aslurry of 3,3',4,4'-biphenyltetracarboxylic dianhydride (2.7181 g,0.0092 mol) in 3 mL (46.7% w/w) of NMP was added and washed in with anadditional 5 mL of NMP to afford a 29.6% (w/w) solution. The reactionwas stirred at room temperature for 24 h under nitrogen. The inherentviscosity of the amide acid oligomeric solution (0.5% in NMP at 25° C.)was 0.22 dL/g. Approximately 10.84 g of amide acid oligomeric solutionwas used to cast an unoriented thin film. Toluene (60 mL) was added tothe remaining amide acid oligomeric solution and the temperatureincreased and maintained at ˜180° C. for ˜16 h under a nitrogenatmosphere. As cyclodehydration to the imide occurred, a precipitateformed. The mixture was cooled, the Toluene (60 mL) was added to theremaining amide acid oligomeric solution and the temperature increasedand maintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, a precipitate formed. Themixture was cooled, the oligomer was washed in hot water, warm methanol,and dried under vacuum at 230° C. for 4 h to provide a tan powder (2.27g, 40% yield). The T_(g) of the uncured as-isolated oligomer (DSC, 20°C./min) was not detected by DSC and the exothermic onset and peak waswashed in hot water, warm methanol, and dried under vacuum at 230° C.for 4 h to provide a tan powder (2.27 g, 40% yield). The T_(g) of theuncured as-isolated oligomer (DSC, 20° C./min) was not detected by DSCand the exothermic onset and peak occurred at 290° C. and 368° C.,respectively. The T_(g) of the cured polymer (cure conditions: 350° C./1h/sealed pan) was not detected by DSC. The unoriented thin films castfrom a NMP solution of the amide acid oligomer cured at 100°, 225°, and350° C. for 1 h each in flowing air was brittle. The T_(g) of the curedfilm was not detected by DSC. Polymer characterization is presented inTable 1.

EXAMPLE 17 3,5-Diamino-4'-phenylethynylbenzophenone and3,3',4,4'-Biphenyltetracarboxylic Dianhydride, Using 10.80 mole %Stoichiometric offset and 21.60 mole % 4-Phenylethynylphthalic Anhydride(Calculated (M)_(n) =5000 g/mole)

The following example illustrates the reaction sequence in equation 4for the preparation of the controlled molecular weight PEPI where R is a4-benzoyl group and Ar is 3,3',4,4'-biphenyl and W is a phenylethynylgroup located in the 4 position. The stoichiometric imbalance is 10.80mole % and the endcapping reagent is 21.60 mole % of4-phenylethynylphthalic anhydride. ##STR48##

Into a flame dried 100 mL three necked round bottom flask equipped withnitrogen inlet, mechanical stirrer, and drying tube were placed3,5-diamino-4'-phenylethynylbenzophenone (2.8499 g, 0.0091 mol) and 4 mL(40.8% w/w) of N-methyl-2-pyrrolidinone (NMP). After dissolution, aslurry of 3,3',4,4'-biphenyltetracarboxylic dianhydride (2.3944 g,0.0081 mol) and 4-phenylethynylphthalic anhydride (0.4892 g, 0.0020 mol)in 4 mL (41.1% w/w) of NMP was added and washed in with an additional 5mL of NMP to afford a 29.9% (w/w) solution. The reaction was stirred atroom temperature for 24 h under nitrogen. The inherent viscosity of theamide acid oligomeric solution (0.5% in NMP at 25° C.) was 0.21 dL/g.Approximately 9.95 g of amide acid oligomeric solution was used to castan unoriented thin film. Toluene (60 mL) was added to the remainingamide acid oligomeric solution and the temperature increased andmaintained at ˜180° C. for ˜16 h under a nitrogen atmosphere. Ascyclodehydration to the imide occurred, a precipitate formed. Themixture was cooled, the oligomer was washed in hot water, warm methanol,and dried under vacuum at 230° C. for 4 h to provide a brown powder(1.75 g, 32% yield). The T_(g) of the uncured isolated oligomer (DSC,20° C./min) was not detected by DSC and the exothermic onset and peakoccurred at 299° C. and 376° C., respectively. The T_(g) of the curedpolymer (cure conditions: 350° C./1 h/sealed pan) was not detected byDSC. The unoriented thin films cast from a NMP solution of the amideacid oligomer cured at 100°, 225°, and 350° C. for 1 h each in flowingair was brittle. The T_(g) of the cured film was not detected by DSC.Polymer characterization is presented in Table 1.

Oligomer and polymer characterization is presented in Table 1,unoriented thin film properties are presented in Table 2, preliminarytitanium (Ti) to Ti tensile shear adhesive properties are presented inTable 3, and preliminary composite properties are presented in Table 4.

What is claimed is:
 1. A diamine containing pendent phenylethynyl groupshaving the following general structure: ##STR49## wherein R is a radicalselected from the group consisting of: ##STR50##
 2. The diaminecontaining pendent phenylethynyl groups of claim 1 wherein R is equalto: ##STR51##